Currently, Thin Film Transistor-Liquid Crystal Display (TFT-LCD) occupies a dominant position in the display market. In the TFT-LCD, image display is implemented by controlling a gray-scale voltage applied to a pixel electrode of each sub-pixel. That is, when an ON voltage is applied to a gate line of a certain row, Thin Film Transistor (TFT) connected with this gate line is turned on, the gray-scale voltage transmitted in a data line is input to the pixel electrode of the sub-pixel, and a voltage difference between the pixel electrode of the sub-pixel and a common electrode determines a deflection state of liquid crystal molecules so as to adjust brightness and display effect of the liquid crystal display.
Typically, the TFT-LCD includes an array substrate, an opposite substrate, and a liquid crystal layer filled between the array substrate and the opposite substrate.
FIG. 1 is a structural schematic view illustrating an array substrate according to one technique. As shown in FIG. 1, the array substrate successively comprises from bottom to top: a glass substrate 11, a gate electrode 12 and a gate line (not shown) disposed in a same layer with the gate electrode 12, a gate insulation layer 13, an active layer 14, a source electrode 15, a drain electrode 16, a data line (not shown) disposed in a same layer with the source electrode 15 and the drain electrode 16, a passivation layer 17 and a pixel electrode 18. The gate electrode 12 partially overlaps with the source electrode 15 and the drain electrode 16, and such overlapping portion results in a coupling capacitance between the gate electrode 12 and the source and drain electrodes 15 and 16, thus a transmission speed of the active layer 14 is decreased.